1. Field
The present invention is related to semiconductor package.
2. Description of the Related Art
Among semiconductor devices, the below-mentioned semiconductor devices have been proposed: That is, as shown in FIGS. 6A and 6B, on semiconductor package in which semiconductor elements have been mounted on wiring boards, electronic components such as either other semiconductor elements or other semiconductor devices are packaged in three-dimensional manners. As to the semiconductor device indicated in FIG. 6A, a semiconductor element 104 stacked on a semiconductor element 102 mounted on a one-sided plane of a wiring board 100 by the flip chip method is electrically connected to the one-sided plane of the wiring board 100 by employing a plurality of wires 106, 106.
Also, another semiconductor device having a POP structure represented in FIG. 6B has been proposed. As to the semiconductor device shown in FIG. 6B, a second semiconductor device 204 stacked on a first semiconductor device constructed of a semiconductor element 202 mounted on a one-sided plane of a wiring board 200 by the flip chip method is electrically connected to the one-sided plane of the wiring board 200 by employing a plurality of connection terminals 206, 206.
In any of the above-described semiconductor devices shown in FIGS. 6A and 6B, an underfill agent 108 (208) is filled into a gap between the wiring board 100 (200) and the semiconductor element 102 (202).
The above-explained underfill agent 108 (208) is filled into the gap between the semiconductor element 102 (202) and the wiring board 100 (200) by dropping a fluid type underfill agent from a nozzle (not shown) located in the vicinity of the semiconductor element 102 (202) mounted on the wiring board 100 (200).
However, similarly, in the semiconductor devices indicated in FIGS. 6A and 6B, in order to meet with thin layer requirements, the gap between the wiring board and the semiconductor element mounted thereon is made narrow, so that the dropped fluid type underfill agent can be hardly entered into the gap between the semiconductor element and the wiring board. As a result, the dropped fluid type underfill agent may easily spread along an outer circumferential direction of the wiring board, so that pads to which edge portions of the bonding wires 106 are connected and pads to which the connection terminals 206 are connected may be partially, or entirely covered by the underfill agent, while these pads are provided in the vicinity of the outer circumference of the wiring board 100 (200) shown in FIGS. 6A and 6B.
In order to avoid such an event that the pads are partially, or entirely covered by the above-described fluid type underfill agent, semiconductor package represented in FIG. 7A has been proposed in the below-mentioned patent publication 1.
In the semiconductor package represented in FIGS. 7A and 7B, a concave groove 306 is formed in a solder resist 302 which covers a one-sided plane of a wiring board 300 in order to avoid that the remainder of an underfill agent 308 which is not filled into a gap between a semiconductor element 304 and the solder resist 302 spreads between a semiconductor element 304 mounted in the flip chip method and an outer circumference of the wiring board 300 along an outer circumferential direction of the wiring board 300.
[Patent Publication 1] JP-A-2004-349399
In accordance with the semiconductor package shown in FIG. 7A, as represented in FIG. 7B, spreading of the remainder of the underfill agent 308 along the outer circumferential direction of the wiring board 300 is disturbed by the concave groove 306. As a result, it is possible to avoid that members such as pads provided in the vicinity of the outer circumference of the wiring board 300 are partially, or entirely covered by the underfill agent 308.
However, there are requirements for forming thin layers and requirements for making compact structures with respect to semiconductor packages. As explained with reference to FIGS. 7A and 7B, in the semiconductor package, spaces for forming the concave groove 306 are gradually reduced between the semiconductor element 304 mounted on the wiring board 300 and the outer circumference of the wiring board 300.